The Neuroanatomy Core (Core B) will provide neurohistological and neuroimaging services to all of the Projects of the SCOR. These will include brain sectioning; immunocytochemistry; in situ hybridization; and histochemical staining. These services will be utilized by Project 2 to examine histologial changes and evidence of neuronal injury in brains of animals exposed to chronic intermittent hypoxia, as well as to identify transcriptional changes in the basal forebrain in these animals. Project 3 will utilize the Neuroanatomy Core for examination of the relationship of cholinergic and nitrergic systems in the basal forebrain. Project 4 will use the Core laboratory to examine Nissl and Fos staining in the ventrolateral preoptic nucleus and glycogen content in the brain. Project 5 will use the Core laboratory for histological examination of orexin receptors and target cell populations using in situ hybridization and immunocytochemistry. Project 6 will utilize the Neuroanatomy Core to trace the inputs to the hypoglossal nucleus using retrograde transneuronal viral tracing, as well as histological verification of injection placement and immunocytochemistry when necessary to verify this. All projects will benefit from the microscopy facilities, digital camera, and imaging software available in the Neuroanatomy Core laboratory.